Enemy of Justice is a terrible set. It gave us Destiny Heroes and lots of mech fairies, but most of the cards in there are terrible, and the foils in there near-worthless. I don't think much of Magic Ruler either, but at least there are funny cards like Fire Kraken and Liquid Beast in there to cheer you up when you end up with jack-all.

If you've got the money to afford a box, why not buy a Battle Pack: Epic Dawn box? They're, what, $45 in the US? At least then you get a chance to pull things like Adreus, or Gem-Knight Pearl, or Tour Guide, that people will definitely want.

personally, i agree with the guy above about getting the battle pack over anything else, cause there are far more valuable cards that will sell or trade faster. but magic ruler has the staples like MST and what not.